Propeller for the percussion mechanism of various projectiles.



N. W. AASEN.

PROPELLER FOR THE PERCUSSION MECHANISM OF VARIOUS PROJECTILES. APPLICATION man uov.1 3,1915.

k fl figfi Patented Nov. 14, 1916.

WQQ MM Glmww c a) n w NIELS WALTERSEN AASEN F COPENHAGEN, DENMARK.

'TPROPELLER FOR, THE PERCUSSION MECHANISM OF VARIOUS PROJECTILES.

Specification of Letters Patent.

Patented Nov. 14, rain.

Application filed November 18, 1915. Serial N 0. 62,164.

To all whomz'tjmay concern Be it known that I, NIELS WALTERSEN AAsEN, a citizen of the Kingdom of Norway, residing at No. 20 Carl Lunds Gade, Oopenhagen, Denmark, have invented new and useful Improvements in Propellers, for the Percussion -Mechanism of Various Projectiles, of which the following is a specification.

In naval torpedoes, aviation bombs, quick-burning grenades, and illumination projectiles discharged from tubes, a propelling device is generally used which is joined, either directly or indirectly to the percussion pin or bolt, but always based on the following principle: The air pressure acts on the propeller which thereupon screwing itself into a female thread, releases the striker. By striking upon a priming charge, the latter can then insure the bursting of the projectile upon the latter meeting an obstacle. However, the type of propeller generally used has the following drawbacks: If the dimensioning of the propeller is sufficiently great, to enableone to be certain of the striker being released in consequence of the screwing into the female threaded part, even when the projectile is only thrown a short distance, that isto say, when traveling at low velocity, the propeller will oppose a certain resistance when that same projectile will be thrown to a great distance; that is to say, when traveling at a higher velocity. The resistance in question will manifest itself: 1. By a considerable slowing down of the velocity of the projectile. 2. By a perturbing action perpendicular to the'direction of the projectile, which latter will then assume an erratic movement. In order to avoid both these drawbacks it will be necessary to reduce the dimensioning of the propeller and then the use of this propeller for throwing grenades at short distances, such as 30 meters (about 32 yards), for instance, can not be'thought of. As a matter of fact, giving the grenade too curved a trajectory must not be thought of, and, on the other hand, a certain velocity will be required,

. in order that the propeller may properly release the striker. On the other hand, the

' shock will be imparted to the propeller upon the percussing of the projectile; it will therefore be necessary to make it of somegreater difficulty forits movement in the air. From a manufacturing standpoint, the cost w1ll be increased. That is why an accessory part is sometimes used, the object of which consists in bearing the shock when the pro jectile percusses.

,The accompanying-drawing shows the device suggested for obviating these several drawbacks.

Figure 1 shows a plan view. Fig. 2 shows a side elevation.

The propeller is of conical or pointed shape and made of thin metal. The lower edge of the cone is turned back at right angles to the axis of the propeller and so as to form inclined winglets. The wings are thus bent back at right angles to the axis of ,the propeller, and slightly turned downward. This particular shape will enable the propeller to offer only a slight resistance when the propeller flies through the air, and, on the contrary, to be highly sensitive to the action of air resistance, to insure the propeller rotating. The working of this type of propeller will therefore be as reliable when the flight of the projectile is at the rate of 10 meters (about 10 yards) per second, as when the speed is 100 meters (about 109 yards) per second. In addition to this, there will be no lateral perturbation ofthe projectile. Finally, the conical shape increases considerably the propellers own resistance. It may therefore be made of a thin and light metal, and yet be used for percussing direct on the obstacle.

I claim l. A propeller for percussion mechanisms for projectiles of the character specified, having a central part of a conical shape, provided with wings bent back at right angles to the axis of the propeller and slightly turned downward.

2. A propeller for percussion mechanisms of projectiles of the character specified, 7

.my invention, I have signed my name in presence of two subscribing wltnesses.

NIELS WALTERSEN AASEN. Witnesses:

CHRISTINE PERPERsEN,

ANNA W. AASEN. 

